土壤和叶面铅污染对铅在水稻体内的分布和积累的影响

Effects of lead pollution in soil and on leaf on distribution and accumulation of lead in rice

摘要:

分别采用土壤添加和叶面喷施Pb(OAC)2·3H2O的方式，进行了黄棕壤盆栽水稻Pb污染试验。结果发现：当土壤添加的Pb量为2000 mg/kg时，水稻地上部分干重与对照相比下降显著，产量无显著变化。叶面Pb污染对水稻地上部分干重和产量均无显著影响。无论是土壤Pb污染还是叶面Pb污染，随着外源Pb污染浓度的增高，水稻植株各部分Pb含量也相应增高，其大小顺序在土壤污染时依次是根＞叶＞茎＞籽粒，叶面污染时是叶片＞根＞茎＞籽粒；不管是土壤Pb污染还是叶面Pb污染，水稻叶片的Pb含量与籽粒Pb含量之间的相关性显著。通过计算得出了水稻籽粒Pb含量与外源Pb污染浓度之间的相关性拟合曲线，从而进一步计算得出黄棕壤总Pb含量毒性临界值是95.7 mg/kg, 叶面污染溶液Pb的毒性临界值在实验条件（喷施9次，每次200 ml）下为46.2 mg/L。

Abstract:

A Pb pollution pot experiment was conducted by adding Pb(OAC)2·3H2O in a yellowbrown soils and spraying it to rice leaf. The results showed that: when the added Pb was 2000 mg/kg, the aboveground dry weight of rice decreased significantly, but the yield of rice didn’t change significantly. Leaf Pb pollution had no significant effect on the aboveground dry weight and yield of rice. Pb concentration in every organ of rice increased significantly as Pb concentration increased, Pb accumulation order in rice organs was root > leaf > stalk > seed in soil pollution and leaf > root > stalk > seed in leaf pollution. Pb concentration in the leaf was significantly correlated with Pb concentration in the seed. A curve was established for fitting Pb concentration in the seed and added Pb concentration, and according to the curve, the toxicity threshold value of Pb total concentration is 95.7 mg/kg in the yellowbrown soil and the added Pb threshold value is 46.2 mg/L on the rice leaf under the experimental condition, i.e., 9 spraying time and 200 ml per time.